//      图片缓存
	export const image_cache = (image_url,image_name,call_back) => {
		
		uni.getStorage({
			key: image_name,
			success:function(res){
				call_back(res.data)
			},
			fail:function(res){
				// 本地没有缓存 需要下载 
				uni.downloadFile({
					url: image_url,
					success: (res) => {
						if (res.statusCode === 200) {
							call_back(res.data)
							uni.setStorage({
								key:image_name,
								data:res,
								success:function(){
									
								}
							})
						}
					}
				}); 
			}
		})
	}
